It has been known since the 1990's that white light-emitting diodes (hereinafter “LEDs”) can provide light that in some ways reproduces incandescent or fluorescent lighting systems with higher efficiency. These LEDs also emit light almost instantaneously (very fast turn on) and also stop emitting light almost instantaneously as well (very fast shut down response). However, until recently these LEDs were not showing sufficient power output in a single unit to provide ambient lighting or to be part of lamps and luminaires. For a few years, LEDs have been a part of flashlights or small lighting devices that can be used for leisure or as security lighting requiring small electrical power consumption. LEDs have been used for decades as light sources in remote controls and sensors in different types of appliances, industrial applications, and home utilities.
Nowadays, LEDs are developed by many manufacturers in order to make them a part of applications requiring powerful lighting such as headlamps in the automotive industry, lamps in household or industrial applications, and streetlights or luminaires. Advantages associated with LEDs include lower power consumption through an increased electrical to visible light conversion efficiency, longer lifetime, faster switching time, relative directivity of light coming out from them, and compactness allowing special designs to be developed. It is a question of a few years before LEDs will be part of powerful lighting systems replacing currently used incandescent and fluorescent lighting systems.